Mechatronics Systems Engineering - Theses, Dissertations, and other Required Graduate Degree Essays

Receive updates for this collection

Design and Implementation of a Regenerative Shock Absorber

Author: 
Date created: 
2015-04-14
Abstract: 

In this thesis, the development of a novel regenerative shock absorber sized for a passengercar suspension system is studied. In the first phase, DC and AC rotary machines along with charging circuits, to be used in the energy conversion stage of the proposed shock absorber are analyzed. In this analysis, the rotary damping coefficients provided by these systems are obtained following by experimental results.In the second phase, the development of a novel regenerative shock absorber in a proof of concept setting is presented. This system consists of a new linear-to-rotary conversion mechanism called algebraic screw, a gearhead, and a rotary machine. The design and analysis of this system is presented. The linear damping coefficient provided by this shock absorber is obtained. Experimental results are presented that evaluate performance of the proposed system on a small-scale suspension system.In the third phase, the development of a novel regenerative shock absorber sized for a passenger car is presented. The shock absorber includes a simple and highly efficient motion converter stage called ”two-leg mechanism”, a planetary gearhead, and a brushless three-phase rotary machine. The design and analysis of the regenerative shock absorber is presented by considering the linear damping coefficient and efficiency of the electromechanical device. The performance of the regenerative shock absorber is evaluated under sinusoidal excitation inputs for typical amplitudes and frequencies in a vehicular suspensionsystem.In the fourth phase, the effect of nonlinear terms of the shock absorber on linear dampingcoefficient provided by this system is studied. Next, the idea of using a variable externalresistance, provided by the charging circuit, to compensate the nonlinear terms is presented.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Mehrdad Moallem
Department: 
Applied Sciences:
Thesis type: 
(Thesis) Ph.D.

Tissue Characterization and Cancer Detection Based on Bioimpedance Spectroscopy

Date created: 
2015-04-21
Abstract: 

Current research envisions improvement of breast cancer detection at early stages by adding a non-invasive modality, electrical impedance spectroscopy (EIS) to the detection procedure. The accuracy of clinical breast examination (CBE) is highly dependent on the clinician’s experience. EIS enhances the physician’s diagnostics capabilities by providing supplementary diagnostic information. Performing CBE besides EIS effects the electrical measurements of soft tissue. In this research the effect of the applied compression during CBE on the electrical properties is studied in-vitro and in-vivo. EIS is also tested over healthy and tumorous subjects. The correlation between tissue electrical properties and tissue pathologies is identified by offering an analysis technique based on the Cole-Cole model. Additional classification and decision making algorithms is further developed for cancer detection. This research suggests that the sensitivity of tumor detection will increase when supplementary information from EIS as well as the built-in intelligence is provided to the physician.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Farid Golnaraghi
Carolyn Sparrey
Department: 
Applied Sciences:
Thesis type: 
(Thesis) M.A.Sc.

An Environment for Advanced Simulation and Control of Lighting Systems

Author: 
Date created: 
2014-04-24
Abstract: 

Development of smart lighting systems can be considered under different perspectives. While a main business case for smart lighting is energy savings, another important consideration is the level of visual comfort experienced by the occupants. The latter aspect has been documented mainly in the context of the circadian system. A growing body of knowledge is related to the environmental impact of energy consumption related to lighting. The so-called layered lighting design, which aims at an effective combination of artificial and natural light, plays a key role in formal certification procedures for building design. This thesis presents two main contributions to the challenging area of the lighting industry: First, a lighting control scheme is proposed which integrates artificial lighting and daylight harvesting. Secondly, the development of an application programming interface is presented which allows one to integrate a control scheme with a simulated scene. The latter part of the contribution could be particularly beneficial for quasi-real-time validation of a lighting control algorithm against a virtual environment. The simulation environment can be deployed on a cloud environment. The case study discussed in this thesis is a scaled down version of an open-plan office lit through a set of individually addressable LED luminaries. It is further assumed that a second source of luminous flux is available in the form of natural light. The control problem consists of maintaining a level of illuminance which meets the users' requirements while minimizing the energy consumption. The proposed intelligent lighting system is based on an adaptive multivariable control scheme where the parameters of the model are determined through a simple identification procedure. The behaviour of the control system was validated through simulation studies and tested on a small scale room. Test results clearly show that a smart lighting system designed around the layered lighting design paradigm is indeed a compelling business case.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Mehrdad Moallem
Department: 
Applied Sciences: School of Mechatronic Systems Engineering
Thesis type: 
(Thesis) M.A.Sc.

Laser-Scribed Photo-thermal Reduction of Graphene-Oxide for Thin Film Sensor Applications

Date created: 
2015-04-24
Abstract: 

In this thesis, a cost effective, simple and fast method of reduction of Graphene Oxide thin film is proposed. Graphene oxide is a non-conductive material intrinsically and one of the techniques to convert it to conductive material is using laser beam to remove oxygen groups from its surface, in other words, to reduce it. Laser parameters must be optimized for an effective and successful reduction. Thin film of non-conductive Graphene oxide is converted into conductive thin layer by fast laser scribing. Laser variables such as, power, speed, laser head distance to surface need to be selected precisely. Optical and atomic microscopies are used to study the changes of thin film surface. Chemical analysis shows that the reduction is successful and the structure is Graphene and removing of oxygen groups from surface is successful. Electrical properties also confirm the conductivity of scribed Graphene oxide. To show the application of reduced Graphene oxide, laser scribing method is used to fabricate pressure sensors arrays and the final product shows acceptable sensitivity to light touches similar to scrolling with finger on a touch screens. The fabricated sensor array is attachable on any surface for monitoring applied forces or pressure and maintains good electrical conductivity under mechanical stress and thus holds promise for durable sensors. Beside the pressure sensor, reduced Graphene oxide thin film has been used to fabricate temperature sensor. Also thin layer of hybrid (Graphene oxide mixed with silver nano wire) is deposited and patterned in the form of interdigitated capacitor to test the capacitance change of touch sensor.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Woo Soo Kim
Department: 
Applied Sciences:
Thesis type: 
(Thesis) M.A.Sc.

Design, Simulation, and Fabrication of a Lightweight Magneto Rheological Damper

Date created: 
2014-03-05
Abstract: 

Mountain biking has significantly evolved recently, thanks to utilizing cutting-edge technologies in mountain bicycle design and fabrication. In this research we study development of a semi-active suspension system using magneto-rheological (MR) fluid dampers instead of conventional oil based shocks. MR dampers are devices with magnetic field dependent damping characteristics.Low power consumption, high controllability, quick response, and high durability are among the major features of MR dampers. In this work we first investigate the damping characteristics of MR dampers to find out if characteristics comparable to the conventional shocks used in mountain bikes can be achieved. To this end,experimental tests were performed on an off-the-shelf MR damper. The results indicate that damping characteristics similar to the ones used in mountain bikes can in fact be achieved using MR technology.However, requirements such as small weight and wide dynamic range have to be addressed in designing a MR damper for mountain bikes. These considerations are studied in this thesis by formulating a simple design followed by a constrained optimization problem and designing the damper accordingly. Utilizing Finite element modeling and simulation tools are further utilized to fine tune and optimize the design.A prototype MR damper is fabricated after the above design steps are carried out.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Mehrdad Moallem
Department: 
Applied Sciences: School of Mechatronic Systems Engineering
Thesis type: 
(Thesis) M.A.Sc.

An intelligent system for energy-efficient lighting and illuminance control in buildings

Author: 
Date created: 
2014-03-04
Abstract: 

Visual comfort and energy saving are two main aspects of an intelligent lighting system. Although the modern lighting systems have been able to achieve major energy savings through different lighting control strategies, the users’ visual preferences have been generally neglected in these systems. Human perception has always been an important factor affecting the overall performance of a lighting system. Not much of the studies carried out in this field have focused on delivering the desired illuminance to the users. Not to mention that frequent changes or noticeable jumps in the output light levels could also be very annoying for the users. The contribution of this thesis is twofold: First, a robust communication framework was developed which is a major pre-requisite for deployment of any lighting system. The developed framework is responsible for facilitating the communication between various types of hardware such as motion, and light sensors, as well as light actuators in the network. Secondly, daylight harvesting, motion detection, and light level tuning strategies were explored by utilizing the developed lighting system infrastructure. In particular, a lighting control algorithm was proposed for residential and commercial use, which when integrated with a building automation system, can satisfy the visual preferences of the users while reducing the overall amount of energy usage in the system. In open-plan environments, the proposed algorithm is capable of delivering the desired light levels for each occupant. The effectiveness of the developed lighting system and the proposed control algorithm were verified by a proof-of-concept testbed and pilot implementations.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Mehrdad Moallem
Department: 
Applied Sciences: School of Mechatronic Systems Engineering
Thesis type: 
(Thesis) M.A.Sc.

Investigating the Local Membrane Degradation Mechanisms in PEM Fuel Cells

Date created: 
2014-02-27
Abstract: 

As fuel cell industry matures over the years, the reliability and durability issues of this state-of-the-art technology become of greater concern among the researchers of this field. Aiming at durability issues of fuel cells, this research has been dedicated to a novel experimental approach in analysis of local membrane degradation phenomena in PEMFCs, with the aim of shedding light on the potential effects of manufacturing imperfections on this process. Followed by a comprehensive review on historical membrane failure analysis data from Ballard Power Systems’ field operated MEAs, three distinct alternatives have been proposed as potential candidates for initiating or accelerating the local membrane degradation phenomena. Catalyst layer delaminations, catalyst cracks, and local sources of Fenton’s reagents are the three options investigated in the current study. Customized MEAs were designed, fabricated and tested under two different in-situ accelerated-stress-test conditions and extensive post mortem analysis has been done on the end-of-life samples. The observations suggested a significant accelerating effect for iron contamination on membrane degradation process in a global term, leading to remarkably shorter lifetimes, but dismissed the local traces of iron oxide as the local initiators or accelerators of this phenomenon. Studying the potential effects of catalyst-layer delamination revealed that having this defect on the anode side can lead to an extremely thinned membrane, while same anomaly, if placed on cathode catalyst-membrane interface has a negligible effect on the rate of membrane thinning under identical operating conditions. Moreover, a substantial mitigating effect for platinum remainders on the site of delamination has been observed on both tests. Eventually, looking at artificial catalyst layer cracks, it was verified that anode and cathode cracks could have no significant impact on local membrane degradation phenomena. While historically, a great deal of degradation studies has been focused on the cathode side, these findings, when considered as a whole, can change the way industries look at the degradation process. Concluded by these in-situ experiments, anode can actually be considered as a key player in the convoluted degradation process.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Erik Kjeang
Gary Wang
Department: 
Applied Sciences: School of Mechatronic Systems Engineering
Thesis type: 
(Thesis) M.A.Sc.

Analysis of air flow distribution and thermal comfort in a hybrid electric vehicle

Author: 
Date created: 
2014-11-18
Abstract: 

Energy efficiency in Hybrid Electric Vehicles (HEV) affects the vehicle mileage and battery durability. Air conditioning is the most energy consuming system after the electric motor in HEVs. Air flow distribution and thermal comfort in an HEV is studied and simulations are performed to investigate the optimum air distribution pattern for providing thermal comfort while maintaining energy efficiency. To acquire a preliminary understanding of the problem, an analytical model is developed for air flow in a cavity. In the next step, a testbed is developed and different air conditioning scenarios are experimented. For numerical simulations, several turbulence models are verified with the experimental data and the realizable k-epsilon model is selected. After validation, the numerical model is applied to various air conditioning scenarios inside the eVaro cabin. It is concluded that optimum air distribution patterns exist for different thermal loads and personalized ventilation can improve energy efficiency by 30% when only driver is on board.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Majid Bahrami
Department: 
Applied Sciences:
Thesis type: 
(Thesis) M.A.Sc.

Utilization of Internal Resonance in Gyroscope Design

Author: 
Date created: 
2014-11-26
Abstract: 

Coriolis vibratory gyroscopes (CVG) suffer from various error sources including manufacturing imperfections and environmental factors. Most design constraints incorporate having the drive and sense mode natural frequencies equal. This poses a difficult solution called “mode matching” requiring complex and extremely accurate on-chip electronics. The research discussed in this thesis acts as a proof of concept on utilizing well-established phenomena in the field of nonlinear dynamics and vibration in the design of CVG gyroscopes with improved stability against manufacturing imperfections. A significant increase in the sense mode bandwidth is shown by structurally tuning the system to 2:1 resonance between the sense and drive modes respectively. A simplified mathematical model of a two-degree-of-freedom system, having quadratic nonlinearities, is obtained and compared qualitatively to more complex models from literature. Experimental results verify numerical simulations, confirming the hypothesis. Additional bandwidth enhancement possibility is established through simple feedback of nonlinear coupling terms obtained from mathematical models.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Farid Golnaraghi
Department: 
Applied Sciences: School of Mechatronic Systems Engineering
Thesis type: 
(Thesis) Ph.D.

Pushing the Limits of Natural Convection Heat Transfer from the Heatsinks

Author: 
Date created: 
2014-12-19
Abstract: 

This research, which has been done in close collaboration with industrial partners, Alpha Technologies and Analytic Systems companies, aims to push the current limits of natural convection heat transfer from vertical heatsinks, with application in passive thermal management of electronics and power electronics. Advantages such as; being noise-free, reliable, with no parasitic power demand, and less maintenance requirements, make passive cooling a preferred thermal management solution for electronics. The focus of this thesis is to design high performance naturally-cooled heatsinks, to increase the cooling capacity of available passive thermal management systems. Heatsinks with interrupted rectangular vertical fins are the target of this study. Due to the complexities associated with interrupted fins, interrupted rectangular single wall is chosen as the starting point of the project. Asymptotic solution and blending technique is used to present a compact correlation for average Nusselt number of such wall, for the first time. The proposed correlation is verified by the results obtained from numerical simulations, and experimental data obtained from a custom-designed testbed. In the next step, natural convection heat transfer from parallel plates has been investigated. Integral technique is used to solve the governing equations, and closed-form correlations for velocity, temperature, and local Nusselt number are developed for the first time. The results are successfully verified with the result of an independent numerical simulation and experimental data obtained from the tests conducted on heatsink sample. In the last step, to model heat transfer from interrupted finned heatsinks, and to obtain compact correlations for velocity and temperature inside the domain, an analytical approach is used. Numerical simulations are performed to provide the information required by our analytical approach. An extensive experimental study is also conducted to verify the results from analytical solution and numerical simulation. Results show that the new-designed heatsinks are capable of dissipating heat five times more than currently available naturally-cooled heatsinks, with a weight up to 30% less. The new heatsinks can increase the capacity of passive-cooled systems significantly.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Majid Bahrami
Department: 
Applied Sciences:
Thesis type: 
(Thesis) Ph.D.